Coding, decoding, and code sensing mechanisms for sorting apparatus



June 19. 1956 R. GOURDON 2,751,092

CODING, DECODING AND coma: SENSING MECHANISMS FOR SORTING APPARATUSFiled July 22, 1952 16 Sheets-Sheet l eee eS 33e e 'e as l NVEN'T'OPRobert G'aura/dn ATTORNE June 19. 1956 R. GOURDON 2,751,092

CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 2 fi 3 a 106 10c r r x I 12. ,g A 10 12 12136? ,H a 11 1 1Z9 INVENTOR Raer-f G'duP/an v A T T RNEY June 19. 1956Filed July 22, 1952 f 72 if x l l H 7 5 i I 1 E: ii I l I I l I LL R.GQURDON CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTINGAPPARATUS 16 Sheets-Sheet 3 IN VEN R Robert C am-Jan ATTo RNEM June 19.1956 GQURDON- 2,751,092

CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 4 FiB. 7

INV NTO R R0 ber'r Gourd/m ATTORNEY June 19. 1956 R. GOURDON CODING,DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS Filed July22, 1952 16 Sheets-Sheet 5 I N VENToE' Raerf G-aur-dan O km A TTORNEYJune 19. 1956 Filed July 22, 1952 FIG.9

R. GOURDON CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTINGAPPARATUS 16 Sheets-Sheet 6 INVNTOR Rob rf G-aurv on A RNEY June 19.1956 R. GOURDON CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTINGAPPARATUS 16 Sheets-Sheet '7 Filed July 22, 1952 INVEN R0 ber-TG-ouPc/dn ATTORNEY June 19. 1956 R GOURDQN 2,751,092

CODING, DECODING AND com: SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 8 as; if

. 2 INVENTOR 1 RG/aer-T ATTORNEY June 19, 1956 R. GOURDON 2,751,092

CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 9 INVENTOR Robe r-T craurJom Y ATTQENE VJune 19. 1956 Filed July 22, 1952 R. GOURDON CODING, DECODING AND CODESENSING MECHANISMS FOR SORTING APPARATUS Fig/14 122 16 Sheets-Sheet 10 lN VENTO)? Ra Ber-l Gram-Jon ATTORNEY June 19, 1956 R. GOURDON 2,751,092

CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 11 FIG.16

INVENT R R0 ber'f Gourd /QL WM;

ATTORNEY FIG.15

June 19. R GOURDQN CODING, DECdDING AND CODE SENSING MECHANISMS FORSORTING APPARATUS Filed July 22, 1952 16 Sheets-Sheet 12 BY WSW A OP/W57June 19. 1956 GQURDON 2,751,092

CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 13 psi) 1/ 756 1 5 INVENTOR 165 52a 55 3RobertG'ouralw ATTORNE Y June 19. 1956 GOURDON R CODING, DECODING ANDCODE SENSING MECHANISMS FOR SORTING APPARATUS Filed July 22, 1952 FIGZZl6 Sheets-Sheet l4 INVEN R Robert G-aur-z/au ATTORNEY June 19. 1956 RGOURDON 2,751,092

CODING, DECODING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 15 l NVEN'TOR Robert (:oura'o N EXAM WATTORNEY June 19. 1956 R GOURDON 2,751,092

CODING, DECdDING AND CODE SENSING MECHANISMS FOR SORTING APPARATUS FiledJuly 22, 1952 16 Sheets-Sheet 16 179' 178 17 179II\ 783 157 l 1778 i I aJ 9 176 m \I \'\-\'\/F 178a ll I o O 7 184 /155J INVENTOR Robert our-d0M ByMwMLZ ATTORNEY United States CODING, DECODING, AND CODE SENSIN GMECH- ANISMS FOR SORTING APPATUS Robert Gourdon, Paris, France, assignorto Societe Anonyme dite: Centre dEtudes M. B. A. (Mecaniqne Balistique,Armement), Paris, France This invention relates to sorting orclassifying apparatus and particularly to apparatus for sortingindividual articles into a large number of classifications. It isdescribed herein as applied to apparatus for sorting mail in accordancewith its destination. Certain features of the invention are ofparticular utility in connection with mail sorting apparatus, whileother features are of more general utility.

This application is a continuation-in-part of my copending applicationsfor United States patents, Serial No. 722,197, filed January 15, 1947,for Apparatus for Indexing Articles, now abandoned; Serial No. 765,946,filed August 4, 1947, for Apparatus for Sorting Articles Such as Mail,now Patent No. 2,669,365; Serial No. 17,984, filed March 30, 1948, forMethods and Means for the Sorting and Classification of Documents orArticles, now Patent No. 2,696,919; and Serial No. 252,383, filedOctober 20, 1951, for Portable Indicating Holders and SettableIndicators Therefor. The last mentioned application is itself acontinuation-in-part of Serial No. 765,946,.Serial No. 17,984, abovementioned, and Serial No. 722,198, filed January 15, 1947, for Holderswith Adjustable Identifying Codes and Arrangements Relat ing Thereto(now abandoned).

The subject matter of this application may he used with the conveyingapparatus for use in a sorting or classification system disclosed in myapplication Serial No. 17,984 filed March 30, 1948, now Patent No.2,696,919.

A complete system for sorting or classification of articles andutilizing the present invention includes a number of portable holdersfor the articles, which may be letters. These holders carry settableindicating elements by which the classifications of the articles, suchas the destinations in the case of letters, may be registered so as tobe apparent to a sensing mechanism. The system includes a sorting orindexing station, at which the letters are inserted in individualholders, which holders simultaneously have their respective indicatingelements set in accordance with the destination of the letter insertedtherein. The holders are then transferred from the indexing station bymeans of suitable conveying apparatus to a sorting station. Where thenumber of classifications is large, as is the usual case in mailclassifying apparatus, the holders may pass through one or morepre-sorting stations before reaching the final sorting station.

At each pre-sorting station, there are provided one or more sensingmechanism to check each holder to determine the setting of theindicating elements thereon. Each sensing mechanism is set for apre-determined destination or group of destinations according to anestablished code. When it encounters a holder Whose indicating elementsare set for that destination or group, it withdraws that holder from theconveyor which brought it to the pre-sorting station and transfers it toanother conveyor which directs it either to a second preatent O sortingstation, there are provided similar sensing mechanisms, each of whichunloads the letters or other articles from those holders whoseindicating elements are set in its code.

Appplication Serial No. 252,383, mentioned above, shows and claims theportable indicating holders and the settable indicators used in thoseholders. Application Serial No. 17,984, also mentioned above, shows andclaims the conveyor apparatus used between the stations in the systemand the means for loading and unloading holders into that conveyorapparatus. The present application is directed to the indexing or codingmechanism by which the indicators on the holders are set in accordancewith the destinations of the letters and also to the code sensingmechanism which control the movement of the holders through a successionof branching paths to a particular receiving bin.

An object of the invention is to provide mechanism for simultaneouslysetting a plurality of indicator elements in different selectedpositions.

Another object is to provide improved setting mechanism of the typedescribed, in which each indicator element is movable to a plurality ofpositions, and including means for selecting any of a large number ofcombinations of positions for said elements.

Another object is to provide improved apparatus for placing articles tobe classified in individual holders, and simultaneously settingindicator elements on the holders to register the classifications of theindividual articles placed therein.

Another object is to provide improved means for sensing the codesettings of a number of indicator elements simultaneously and forperforming control operations in accordance with such settings.

Another object is to provide improved code sensing apparatus of the typedescribed, together with means responsive to that code setting todetermine the path of travel of the holder from the sensing apparatus.

Another object is to provide improved code sensing apparatus of the typedescribed together with means responsive to that code setting toempty-the holder.

The foregoing and other objects of the invention are attained byproviding at the indexing station a mechanism for setting the indicatorelements on the holders, which operation is hereinafter referred to ascoding? a control panel for the coding mechanism, and means for makingvisible to an operator at the control panel the sorting station or to afinal sorting station. At the final letters being placed in the holders.The control panel includes a number of selectively operable switches,one for each classification. As each letter becomes visible, theoperator actuates a switch corresponding to its destination. Each switchwhen operated causes the energization of a plurality of electromagnetsin a controller. The controller preselects a number of indicator settingtools to be moved on a subsequent control operation and also preselectsthe distances through which the respective setting tools are to move inthat control operation. The selection is determined by the particularelectromagnet or electromagnets controlled by the switch. After thepreselection is complete, the operator moves a control lever whichcauses the letter to be inserted in a holder and also causes theselected indicator setting tools to engage and set the indicatorelements on that holder. As each holder approaches the position where itreceives a letter and has its indicating elements set, it passes adecoding device which resets all its indicating elements to apredetermined neutral position so that all the indicating elements arein that position when they are engaged by the setting tools of thecoding mechanism.

After a letter is inserted in a holder and the indicating elements onthe holder are set, the holder is transferred by suitable'conveyorapparatus to a 'presorting or final 3 sorting station. When a holdercarrying a letter reaches a pre-sorting or final sorting station, a codesensing mechanism is moved into engagement with its indicating elements.This sensing mechanism is set for a predetermined code or group ofcodes. When it encounters a holder whose code corresponds to thissetting it seizes that holder and withdraws it from the conveyormechanism on which it has been moving and transfers it to anotherconveyor leading eventually to an unloading station. At the unloadingstation another code sensing mechanism checks the code of the indicatingelements and if it is correct operates suitable mechanism for emptyingthe letter from the holder into a bin corresponding to its distination.The empty holder is then returned to the indexing station by suitableconveyor apparatus.

Other objects and advantages of my invention will become apparent fromthe consideration of the appended specifications and claims, takentogether with accompanying drawings in which Figure 1 is a perspectiveview of a portable indicating holder for use in the sorting apparatus ofthe invention.

Figure 2 is a fragmentary elevational view on an enlarged scale showinga portion of the holder of Fig. 1 and one of the indicating elementstherein.

Fig. 3 is a cross-sectional view taken on line IIIIII of Fig. 2.

Fig. 4 is a perspective view, with certain parts broken away, showing aconveyor block which is used to transport a plurality of the holders ofFigs. 1-3.

Fig. 5 is a fragmentary sectional view showing a portion of themechanism of the conveyor block of Fig. 4.

Fig. 6 is a perspective view of the front end of an indexing station,with certain parts broken away.

Fig. 7 is a somewhat diagrammatic sectional view, of the front end ofthe indexing station of Fig. 6.

Fig. 8 is a fragmentary view, similar to Fig. 7 but on a larger scale.

Fig. 9 is a sectional view taken on the line IX-IX of Fig. 7.

Fig. 10 is a fragmentary view of the control panel of the indexingstation.

Fig. 11 is a detailed sectional view of one of the switches on thecontrol panel of Fig. 10.

Fig. 12 is a wiring diagram showinghow the switches of Fig. 9 controland select groups of electromagnets.

Fig. 13 is a sectional view of an electromagnetic controller whichtranslates the energization of electromagnets of Fig. 12 intopreselections of indicator operating elements.

Fig. 14 is a cross-sectional viewshowing the controller of Fig. 13 andthe indicator setting elements operated by it.

Fig. 15 is a sectional view taken on the line XV-XV of Fig. 14.

Fig. 16 is an enlarged view of part of the controller of Fig. 13, alsoillustrating the-decoding mechanism.

Fig. 17 is a somewhat diagrammatic horizontal sectional view of aportion of a pre-sorting station.

Fig. 18 is a fragmentary somewhat diagrammatic perspective view of thepro-sorting station of Fig. 17, illustrating the principal operatingparts thereof.

Fig. 19 is a cross-sectional view illustrating a code sensing mechanismin the pre-sorting station of Figs. 17 and 18, as it seizes acorrespondingly coded holder.

Fig. 20 is a cross-sectional view taken on the line XXXX of Fig. 19.

Fig. 21 is a fragmentary, somewhat diagrammatic horizontal sectionalview of a final sorting station.

Fig. 22 is a fragmentary somewhat diagrammatic'perspective view of thefinal sorting station of Fig. 21.

Fig. 23 is a perspective view of a code sensing and holder openingmechanism in the final sorting station.

Fig. 24 is a fragmentary sectional elevational view 4 of the codesensing and holder opening mechanism of Fig. 23.

Fig. 25 is a cross-sectional view of a holder closing mechanism formingpart of the final sorting station.

FIGS. 1 TO 3.THE HOLDER These figures illustrate a portable indicatingholder 1, which is more completely described and claimed per '-se in mycopending application, Serial No. 252,383, previously mentioned.

The holder 1 is constructed in the shape of a pocket, open at its upperend and comprising a front wall 2, a rear wall 3, and thickened sidewalls 4. Outer and inner reinforcing plates 5 and 6 are shown coveringthe side walls.

The pocket has a bottom flap 7 in the form of a plate riveted on thelower part of the wall 2 and sufliciently flexible so that it may beopened. When the flap is opened, the holder pocket is emptied bygravity.

The bottom flap 7 is self-biased to its closed position, in whichposition it engages the rear wall 3. It may be opened by means of a pairof opening rods 8 which extend downwardly through suitable guides withinthe pocket, and have their lower ends engaging the flap 7. The upperends of the rods 8 are accessible through the open top of the pocket andare provided with flanges 8a. When the rods 8 are depressed to open theflap 7, the flap engages the outer surfaces of the rods and frictionallyholds them against the rear wall 3. The flap 7 is thereby maintainedopen until the rods 8 are positively moved upwardly. This upwardmovement of rods 8 may readily be accomplished with the aid of flangesSo, either manually or with a suitable mechanical device for engagingand lifting these flanges.

The rear wall 3 is longer vertically than the front wall, so as toprovide upper and lower extending flanges. Bot h flanges are adapted toengage slots in a supporting striicture so that the holder isheld'vertical. The upper flange is provided with a central notch 3a andthe lower flange with notches 3b near its ends. These notches may beengaged by supporting or guiding rails so as to maintain a stack orgroup of holders in alignment.

Four pieces 9 in the shape of flat inwardly opening hooks are attachedto the upper and lower ends of the side walls 2. Thesehooks facilitateendwise movement of the holder, either manually or by a mechanicaldevice.

The side walls 4 are each provided with a number of recesses 10 (Fig.3). The reinforcing plates 5 are provided with openings 11 aligned withthe recesses 10. An indicating element 12 is located in each of theserecesses.

Each indicating element 12 comprises a cylindrical body with a conicalrear end 12a, and a diametrical rib 12b on its front end. The rib 12bhasradially projecting tips 120.

The recesses 10 are generally of the same form as the elements 12. Eachrecess 10 has a cylindrical portion 10a which receives the body of theelement 12 and is slightly larger in diameter so that the body is freelyrotatable therein. The outer end of this cylindrical portion terminatesat a tapered shoulder 10b leading to another cylindrical portion 100 ofenlarged diameter. The tips are rotatable and translatable in theportion 10c of the recess. Engagement of tips 120 with shoulder 10blimits the inward movement of the element 12, whereas engagement of tips12c with the edge of plate 5 limits its outward movement.

The edge of plate 5 around each opening 11 is bent inwardly to form afrusto-conical portion 11a, and notches 11b are cut therein. Thesenotches are provided in diametrically opposed pairs.

Each indicatingelement 12.is biased toward the.outer end of its recessby a 'flexible leaf spring 1 3 which; is

shown as being formed from the inner reinforcing plate 6 by a stampingand cutting operation. The conical end 12a of the indicating elementprojects into an opening 13a formed in the leaf spring 13. When the rib12b is aligned with a pair of notches 11b, the leaf spring 13 holds therib in the notches and angular movement of the element 12 is therebyprevented.

In order to change an element from one angular position to another, itis necessary to push it inwardly in opposition to the leaf spring 13 soas to release it from the two notches with which it has been engaged,and then to turn it while holding it inwardly. If the element 12 isturned to bring the rib 12b into alignment with another pair of notchesand then released, the leaf spring 13 again forces the rib forward intothe new pair of notches, thereby retaining the element in a new angularposition. It is almost impossible for any accidental impact or vibrationto produce a combination of forces that would be capable of translatingand rotating an indicating element to change its indicating positiononce it has been set in the notches 11b. Furthermore, since the element12 is always held securely completely within the recess 13, it cannotreadily come into contact with any external object which mightaccidentally change its position. The inwardly bent portion 11a of theplate blocks the outer end of the recess sufiiciently to preventmovement of the element out of the recess and to protect the elementagainst accidental contacts with external objects.

The side walls 3 and plates 5 are provided with a central, inwardlytapered recess 5a which cooperates with other structures to be describedso as to guide and center the holder 1.

The positions of the indicating elements are observable from outside theholder, either by visual inspection or by the use of sensing tools. Itshould be noted that the observation of these elements can be carriedout either one element at a time or all elements simultaneously. Whencarried out simultaneously, a number of tools must be used,corresponding to the number of elements. Furthermore, these sensing oridentifying operations can be performed when the holders are stacked,since the indicating elements are located in the side walls of theholders, which side walls are accessible when the holders are stacked.

Each indicating element has four distinguishably different indicatingpositions. Each element by itself is therefore capable of giving fourindications, each having a meaning established by any arbitrarilyselected code. For example, the position shown in Fig. 2, wherein therib 12b is vertical, may be called the normal position. The element 12may be rotated to three other indicating positions, respectively 45, 90and 135 from the normal position. If two elements are used together,there are sixteen possible combinations of element positions andtherefore sixteen different possible code indications. Eleven elements,as shown in Fig. 1, can give a number of indications equal to four tothe eleventh power, or 4,194,304.

When these holders are used, for example, in a mail sorting system, itis possible that a simple system might only require fourclassifications, and it would then be only necessary to use oneindicating element on each holder. In a very complex sorting system,there may be thousands of classifications. In such a system, acombination of indicating element positions for each classification isestablished by an arbitrarily assigned code.

It would be possible to use one group of two or three elements toestablish a state classification, another group to establish a cityclassification, etc.

Since indicating elements are provided on both ends of the holder, it ispossible to have the holder indicating elements set or coded at bothends. In that event, a sensing device adjacent one end of the holder cancheck it for one code while another sensing device at the oppo- 6 siteend of the holder checks it for a different code at the same time.

In a complex system, several successive sensing or identifyingoperations may be required. It is therefore essential that the positionof the indicating element should not be disturbed by the sensingoperation. The structure described above meets this requirement, sincethe positions of the indicating elements may be sensed by a linearmovement of the sensing tool, while a change in position or setting ofthe element requires a linear movement of the setting tool followed by arotary movement.

FIGS. 4-5 .CONVEYOR BLOCK The conveyor block as illustrated in thesefigures is shown and claimed per se in my copending application many ofthe advantages of the invention claimed herein.

As shown in Fig. 4, the conveyor block comprises a box-shaped frame 14,of generally rectangular cross-section and having its sides open. Theinner surface of the top and bottom of the frame 14 are corrugated orgrooved as shown at 15, for the purpose of receiving the top and bottomedges of the rear walls 3 of the holders 1 when they are slid laterallyinto the conveyor block. When the top edge of a wall 3 is received inone of the upper grooves and the bottom edge in the opposite lowergroove, the holder is maintained vertical, even though there are noother lateral supports.

The side edges of the frame 14 are reinforced by outwardly extendingflanges 16 and 17, illustrated as being of channel-shaped cross-section.Hollow cross braces 18 are provided between the side flanges 16 and 17at the four corners of the block and at the center of its top andbottom, as shown in Fig. 4. The side flanges and braces contribute tothe stiffness of the block and also serve as locating surfaces forpositioning the blocks accurately at the various working stations. Theyare also used as gripping surfaces when transferring the blocks from oneconveyor to another.

When the receptacles are placed within a block, they may be locked thereby a rod 19 which extends longitudinally of the block adjacent themiddle of the top of the frame 14. In its unlocking position, rod 19 isabove the top of the frame 14, so that it is outside the frame. Theframe 14 has an elongated central aperture 14a just under the rod 19.The rod 19 may move downwardly through the aperture 14a and engage thenotches 3a in the centers of the upper edges of the holders 1 within theblock. When the holders 1 are so engaged by the rod 19, they are lockedagainst transverse movement out of the block.

The rod 19 is supported on the ends of arms 21 attached to a shaft 20journaled on spaced supports 20a, which are mounted on the frame 14. Atorsion spring 22 encircles the shaft 20 and biases it to the positionshown in Fig. 5 wherein the rod 19 has moved downwardly through theaperture 14a into a position to engage the holders 1 within the block.The ends of shaft 20 extend beyond the ends of frame 14, and both endsof the shaft 20 are provided with downwardly depending hooked arms 23which may be utilized to rotate the shaft and lift the rod 19 to unlockthe holders 1. For example, the arm 23 may be rotated by verticalmovement of the block into a position where the arm 23 engages astationary lug 24 (see Fig. 5).

Notches 25 are provided in the end portions of the side frame members 16and 17, for guiding and supporting the blocks at certain times. Thesenotches are located 7 below the lowest position of the arm 23, so that amember inserted into the two notches and spanning the block does notengage the arm 23.

FIGS. 6l6.-INDEXING STATION Figs. 6-9, mechanism for handling letters,holders and blocks The indexing station is an apparatus or machine inwhich incoming letters are placed individually in holders and theholders have their indicating elements set or coded in accordance with apre-established code to indicate the destinations of the letters. Theindexing station receives unsorted letters and blocks filled with emptyholders whose indicating elements are set at random, and dischargesblocks filled with holders each containing one letter and having itsindicating elements set or coded to indicate the destination of thatletter.

The path of movement of the letters into the machine will first bedescribed. The letters are inserted in the machine in a stack such asshown at 26 in Fig. 7. The stack rests, in a chute 27 which slantsdownwardly toward the operators end of the machine which is at the rightin Fig. 7. A suitable weight 28 is placed in the chute behind the stack26 to force the letters forward. A belt 31 supported on suitable rollers32 forms a portion of the bottom of the chute 27 and facilitates theforward movement of the stack 26. A glass plate 29 extends across thefront of the chute, so that the leading letter in the stack is pressedagainst it, and the address on that letter is visible through the glassto the operator in front of the machne. A lamp 30 is suitably mountedabove the plate 29 to illuminate the leading letter. Near its forwardend the bottom of chute 27 is provided with one or more apertures 33,which are connected to any suitable source of air under light pressure.The air issuing from the apertures 33 separates the leading letter inthe stack from those behind it and presses it lightly against the plate29. The plate 29 is slanted slightly, with its lower end extendingforward and spaced from the front end of the chute.

A mechanism is provided for removing the front letter from behind theplate 29 and conveying it downwardly along a guide wall 37 into a holder1 positioned below it. The holder which receives the letter is theforward one of a stack of several such holders which are passing throughthe machine. As the letter travels from the glass plate 29 to the holder1, it passes through a mechanism which cancels the stamp on the, letter.

The mechanism for conveying the letters downwardly from behind the plate29 to the holder 1 includes a shaft 34. rotatably mounted below thefront end of chute 27. Aroller 35 is fixed on the shaft 34. A resilientblade 36 is wrapped around the roller 35, and has one end projectingupwardly along the guide wall 37. The blade 36 carries at that end aletter-driving plate 38 having a roughened outer surface and a taperedupper end 38a. The shaft 34 is pivoted to and fro through apredetermined angle in synchronism with certain other parts of themechanism to be described later. As the shaft 34 rotatescounter-clockwise, the plate 38 moves upwardly behind the forward letterin back of the plate 29. On its return downward movement, the roughenedsurface, aided by gravity, carries the letter along with it, the letterpassing between the plate 38 and a spring loaded roller 39. Theextension plate 38 doesnot move upwardly all the way to the top of theletter, but only engages a portion of the. back, surface thereof.

On theshaft 34 is fixed an arm 40 to which is pivotally connected a rod41 extending upwardly and engaging the lower surface of a plate 42 whichruns in a channel 43 provided in the guide wall 37. A spring 44 biasesthe plate 42 downwardly, so that it moves in synchronism with the blade36 and" its extension 38.

Opposite the guide wall 37 and attached to the frame of the machine area pair of brackets 45, pivotally supporting at their ends a pair ofupstanding arms 46 which carry at their upper ends a cross-shaft 47. Thecrossshaft 47 has fixed on it a pair of projections 48 which extendtoward the plate 42 and also has fixed on it a pair of downwardlyextending arms 49 carrying between them a printing roller 50. A spring51 biases the levers 46 rearwardly, toward a position wherein theprojections 48 engage the front of the letter as it moves downwardly,and hold it tightly against the guide wall 37 and the plate 42. When theletter and the upper end of the plate 42 both clear the ends of theprojections 48, the channel 43 is open to receive the projections 48.This allows the lever 46 to move counter-clockwise under the influenceof the spring 51 so that the printing roller 50 is carried against theface of the letter, thereby cancelling the stamp. The letter continuesto move downwardly between rollers 52 pivotally mounted on the brackets45 and rollers 53 pivotally mounted on arms 54 carried by the shaft 34.After passing between these rollers, the letter drops into a pocket in aholder 1 positioned immediately beneath it.

The path of movement of the blocks 14 and holders 1 through the indexingstation will now be described. Referring to Fig. 9, a suitable conveyor(not shown) delivers blocks 14 such as that illustrated in Figs. 4 and5, filled with empty holders 1, to a receiving location at the top ofthe indexing station and generally indicated at 55. From the receivinglocation 55, each block of empty receptacles is moved downwardly bysuitable mechanism which is shown and described more completely in mycopending application Serial No. 17,984 mentioned above. In its travelthrough the indexing station, each block 14 moves downwardlyintermittently, and stops successively at an unloading location 56, areloading location 57 and a discharging location 58. Each block movesdownwardly from one location to the one below as soon as the lowerlocation is empty, that is to say, when the block previously occupyingthat station has moved onward. As a block enters location 56, a fixedlug 24 engages the hooked arm 23 on the block and rotates itcounter-clockwise sufiiciently to unlock the holders carried by theblock.

Parallel to the block in its location 56 are a pair of upper conveyorbelts 59 and lower conveyor belts 60. The conveyor belts 59 and 60 aregrooved or corrugated to receive the upper and lower edges of the rearwalls 3 of the holders 1.

The conveyor belts 50 and 60 define between them a storage chamber 61for empty holders unloaded from a a block 14- at location 56. Theconveyor belts 60 extend around a pulley 62 (see Fig. 7) and above athird set of grooved conveyor belts 63. The belts 60 and 63 definebetween them a storage chamber 64 for holders which have been loadedwith mail and which have had their indicating elements set to indicatethe destination of the mail. The belts 59, 6t and 63 are driven bymovement of the holders themselves, by mechanism to be described later.The holders travel with the belts 59, 60 and 63 in the directionsindicated by the arrows in Fig. 7. They move forwardly with the belts 59and 60 until they reach the forward end of'chamber 61, at which timethey are located laterally between two coding units 201 (see Fig. 6).These coding units are effective by means of mechanism to be describedbelow to set the indicating elements in the sides of each holder as aletter is dropped into the holder from above. After each holder has aletter placed in it and its indicating elements coded, it is moveddownwardly to a position at the forward end of the storage chamber 64.It is then pushed rearwardly into the chamber 64. When the chamber 64 isfilled, the leading holder in that chamber engages a control switch andstarts the operation of a loading and unloading mechanism describedbelow, which transfers the filled holders in the storage chamber 64 toan empty block waiting at location 57. On its return movement, thismechanism also ex-

